I have put the book on my amazon wishlist.
I'll give you guys the URL and if you feel generous please purchase..
Only kidding but I am looking into it.
I'm looking at getting a 2x Barlow lense for my scope. It already has a 10mm eyepiece and a 25mm wide field so from asking on forums it has been suggested that a barlow is the way to go as I am still learning.
My scope is a 130 diameter parabloic mirror with a 650 long tube.
Skywatcher 130P, won some awards and all round has good reviews.